GS1 AI (Application Identifier) & Element String Specifications

The GS1 Application Identifier (AI) appears after the
Function Code 1 (FNC1) in Code 128, Data Matrix or DataBar Expanded barcodes to encode certain types of information.
Multiple AIs may be encoded in
DataBar Expanded barcodes for use in POS systems, which replace UPC and EAN symbols in the same space or less. This allows serial numbers, sell-by dates and other
information to be easily verified at the point of sale. Encoding examples are available for
Code 128,
DataBar Expanded and
Data Matrix ECC200 barcodes.

When generating GS-1 Symbols, the following rules apply:

The AI is defined by the digits after the FNC1 character,
which must be the first character in a GS-1 barcode. Within all IDAutomation
products, placing parentheses around the AI automatically encodes the FNC1
character.

Multiple fixed length element strings may be included in a single barcode
symbol without additional FNC1 characters, if variable length element strings (such
as those with AIs 10, 21 or 92 as defined below) are included last. This is because
the reading device understands the length of each fixed length element string.

If additional element strings are encoded after a
variable length element string, an
additional FNC1 is required between them to define the end of the previous variable length
element string.

When encoding Data Matrix and DataBar barcode symbols, MOD10 check digits are not
usually included in fixed
length element strings.

The FNC1 character is included in DataBar automatically and is encoded
in DataBar Expanded with parentheses.

A MOD10 check digit is required for some element strings. This check digit
is not always encoded within the barcode. Usually, Code 128 barcodes require the
MOD10 to be encoded while DataBar and Data Matrix do not.